CONFIG_SOC_IMX7D is not available for thedefaultarchitecture x86.
Result is shown for architecture arm

i.MX7 Dual support

modulename: mach-imx7d.ko

and/or

clk-imx7d.ko

configname: CONFIG_SOC_IMX7D

Linux Kernel Configuration
└─>Freescale i.MX family
└─>i.MX7 Dual support
In linux kernel since version 3.10 (release Date: 2013-06-30)  
This enables support for Freescale i.MX7 Dual processor.

source code:
arch/arm/mach-imx/mach-imx7d.c


is selected by
CONFIG_RESET_IMX7